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           Commitments and Contingencies - Total future minimum lease payments (Detail) (USD $) 
        In Thousands, unless otherwise specified  | 
        
           Dec. 31, 2014 
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| Operating Leased Assets [Line Items] | |
| 2015 | $ 461us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent | 
| 2016 | 2,633us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears | 
| 2017 | 2,562us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears | 
| 2018 | 2,490us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears | 
| 2019 | 2,504us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears | 
| Beyond | 30,883us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter | 
| Total minimum lease payments | $ 41,533us-gaap_OperatingLeasesFutureMinimumPaymentsDue | 
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- Definition 
          Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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